Issue #15723 has been updated by Eregon (Benoit Daloze).


shevegen (Robert A. Heiler) wrote:

First, it's Benoit (my first name) or Eregon/eregon, but not `benoit`.

I think it's perfectly fine to include a proposal in addition to the summary, and have that to guide the discussion at the meeting.
@sikachu's comment also includes 2 lines of summary, which seem neutral enough (e.g., I think/I believe).
Anyway, I'm sure MRI committers are already fairly familiar with opinions on this issue.
That proposal is BTW the one done by the author of the current design, @jeremyevans0 since a long time already.
So, I think your critic is out of place (at the very least you should @-mention people you critic, and do so on the ticket you disagree),
but if you want something else for this feature, then feel free to comment here and share your own proposal.

TBH, I didn't see many comments in favor of multiple block arguments.
It would be good if supporters of that would comment here.
To me, it sounds like most people do not want them or are convinced by the arguments above it's not worth it.
So a proposal to remove @2 and above just makes sense, isn't it?

----------------------------------------
Misc #15723: Reconsider numbered parameters
https://bugs.ruby-lang.org/issues/15723#change-80287

* Author: sos4nt (Stefan Schler)
* Status: Feedback
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
----------------------------------------
I just learned that *numbered parameters* have been merged into Ruby 2.7.0dev.

For readers not familiar with this feature: it allows you to reference block arguments solely by their *index*, e.g.

```ruby
[1, 2, 3].each { |i| puts i }

# can become

[1, 2, 3].each { puts @1 }
```

I have an issue with this new feature: I think **it encourages sloppy programming** and results in **hard to read code**.

---

The [original proposal](https://bugs.ruby-lang.org/issues/4475) was to include a special variable (or keyword) with a **readable name**, something like:

```ruby
[1, 2, 3].each { puts it }

# or

[1, 2, 3].each { puts this }
```

Granted, that looks quite lovely and it actually speaks to me  I can *understand* the code. And it fits Ruby: (quoting the website)

> [Ruby] has an elegant syntax that is natural to read and easy to write.

But the proposed `it` / `this` has limited application. It's only useful when dealing with a single argument. You can't have multiple `it`-s or `this`-es. That's why `@1`, `@2`, `@3` etc. were chosen instead.

However, limiting the usefulness to a single argument isn't bad at at. In fact, a single argument seem to be the limit of what makes sense:
```
h = Hash.new { |hash, key| hash[key] = "Go Fish: #{key}" }

# vs

h = Hash.new { @1[@2] = "Go Fish: #{@2}" }
```
Who wants to read the latter? That looks like an archaic bash program (no offense). We already discourage Perl style `$`-references: (from [The Ruby Style Guide](https://github.com/rubocop-hq/ruby-style-guide#no-perl-regexp-last-matchers))

> Don't use the cryptic Perl-legacy variables denoting last regexp group matches (`$1`, `$2`, etc). Use `Regexp.last_match(n)` instead.

I don't see how our code can benefit from adding `@1` and `@2`.

Naming a parameter isn't useless  it gives context. With more than one parameter, naming is crucial. And yes, naming is hard. But avoiding proper naming by using indices is the wrong way.

So please reconsider numbered parameters.

Use a readable named variable (or keyword) to refer to the first argument or ditch the feature entirely.

---Files--------------------------------
implicit-param.diff (20 KB)


-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>